This invention relates to hydrocarbon solutions of organomagnesium compounds and more particularly to hydrocarbon solutions of diorganomagnesium reagents.
Organomagnesium halides, commonly known as Grignard reagents, have wide utility in chemical reactions. By comparison with these organomagnesium halides, diorganomagnesium compounds are employed far less frequently, although such compounds undergo reactions analagous to those of organomagnesium halides. A primary reason for the preference of the Grignard reagents resides in the fact that large amounts of diorganomagnesium compounds are not easily prepared. In general, if such compounds could be readily prepared by methods which do not adversely affect the properties of the organomagnesium compounds, the diorganomagnesium compounds would be preferable both from a cost standpoint and a performance standpoint as compared to Grignard reagents. For example, the diorganomagnesium compounds can be more readily solubilized in hydrocarbon than the Grignard reagent. Moreover, better yields are obtained in numerous reactions employing diorganomagnesium compounds instead of Grignard reagents. In particular the diorganomagnesium compounds are known to be useful in the preparation of various polymerization catalysts. See, for example, teachings of their use in the preparation of Ziegler catalysts in the following: U.S. Pat. No. 3,051,690, U.S. Pat. No. 3,070,549 and U.S. Pat. No. 3,392,159. More recently, it has become advantageous to employ such compounds as the sole or as one of two or more of reducing organo metallic compounds in Ziegler catalysts. As recently observed, the use of such organomagnesium compounds in the manufacture of Ziegler catalysts often results in a catalyst having very high efficiency.
In practices employed heretofore, it has often been necessary to solubilize the organomagnesium compounds by dispersing them in ether, or like polar liquid, prior to use in the preparation of the desired catalyst. Accordingly, it would be highly desirable to devise a procedure for solubilizing organomagnesium compounds without the aid of significant quantities of polar liquids such as ethers, alcohols and the like. In an attempt to obtain this objective, it has sometimes been the practice to disperse the organomagnesium compound in a hydrocarbon liquid by stirring or other mechanical means. Unfortunately such dispersions or suspensions are not very stable. Therefore there is a non-uniform distribution of the organomagnesium compound in the hydrocarbon solvent which is further aggravated by the fact that the insoluble organomagnesium compounds settle from the suspensions or dispersions upon passage of time.
In order to stabilize such dispersions or suspensions, it has been taught in Annalen No. 605,93-97 (1957), and more recently in U.S. Pat. No. 3,737,393, to add an alkyl aluminum compound to the dispersion of dialkyl magnesium compound in hydrocarbon liquid. Unfortunately, catalysts prepared from such organomagnesium complexes exhibit significantly lower catalyst efficiencies at polymerization temperatures above 150.degree. C.
Therefore, it would be highly desirable to solubilize a diorganomagnesium compound in a hydrocarbon solvent in a manner such that catalyst prepared from such hydrocarbon soluble diorganomagnesium compounds exhibit high catalyst efficiencies even at polymerization temperatures above 150.degree. C.